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Showing posts from September, 2012

This Blog Has Moved!

Right, so yes, five years ago I moved to github pages, and never bothered to redirect any of these pages there. Now I've moved on from there, and... Finally I am using my real domain, trishagee.com . My blog is now at trishagee.com/blog .  See you there!
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The Strange Loop

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Last week (was it only last week?) I was at Strange Loop , presenting a workshop on the Disruptor . I didn't really have any expectations from the conference, I've never been before and, if I'm honest, hadn't heard of it before.  So everything was a pleasant surprise. It's a very geeky conference.  I mean that as a compliment, of course.  Lots of very smart people talking about stuff that's waaaay more advanced than you frequently get in the conferences employers would be happy to pay for.  The themes I mostly saw were functional programming and the (insert horribly abused term) Big Data space. So nothing about Spring and Hibernate or any of their ilk, of course.  Almost nothing about Java actually, as if a language that is actually used by millions of developers is somehow too passé.  But this was extremely liberating - if there's nothing that's going to be applicable to my day job, I can go and see talks on things I'm actually interested in
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Strangeloop Disruptor Workshop Materials

On Sunday I gave my very first workshop on the Disruptor.  The aim was to give people some hands-on coding experience using the syntax.  Because time was limited (you can't get people to build an entire application architecture in 2.5 hours) the example is somewhat contrived, and needs a big leap to make it into a proper application context.  But the workshop should: Give an overview of the Disruptor Show how to create a simple one producer, one consumer example. Show how to wire up a parallel event handler Show how to how (and why) to create a diamond dependency graph. Extrapolate beyond these very simple examples to something closer to a real world architecture. Requirements are: Basic Java skills Java 7 update 7 (Optionally) IntelliJ . The slides (not all that useful, I'll grant you, without me talking) are available, and you can download the code . If you want to work through the examples yourself, start with com.mechanitis.towerdefense.TowerDefence .
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Upcoming Events

So yeah... in keeping with this year's theme of basically only blogging about the exciting conferences I've been to, I'm going to blog about the exciting conferences I am attending in the future.  I haven't been great at doing that, the disconnect between the time I submit a presentation and the actual announcement means that I often forget I haven't told anyone about what I'm up to. Firstly, I'm back in the States this month to present my very first workshop - An Introduction to the Disruptor  at Strangeloop.  I've been given a mere 6 months to prepare it (note: sarcasm) and it's still a work in progress.  So, if you're coming, feel free to suggest things you want to see covered.  If you are coming, I'd love to hear from you. Secondly, I'm back in the States again a minute and a half later for several presentations at JavaOne.  I really enjoyed JavaOne last year, it was my first international conference, my first speaking gig, and a
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Apologies for the interruption to your service

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Popular posts from this blog

Dissecting the Disruptor: What's so special about a ring buffer?

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Recently we open sourced the LMAX Disruptor , the key to what makes our exchange so fast.  Why did we open source it?  Well, we've realised that conventional wisdom around high performance programming is... a bit wrong. We've come up with a better, faster way to share data between threads, and it would be selfish not to share it with the world.  Plus it makes us look dead clever. On the site you can download a technical article explaining what the Disruptor is and why it's so clever and fast.  I even get a writing credit on it, which is gratifying when all I really did is insert commas and re-phrase sentences I didn't understand. However I find the whole thing a bit much to digest all at once, so I'm going to explain it in smaller pieces, as suits my  NADD audience. First up - the ring buffer.  Initially I was under the impression the Disruptor was just the ring buffer.  But I've come to realise that while this data structure is at the heart of the patte
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Dissecting the Disruptor: Writing to the ring buffer

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This is the missing piece in the end-to-end view of the Disruptor.  Brace yourselves, it's quite long.  But I decided to keep it in a single blog so you could have the context in one place. The important areas are: not wrapping the ring; informing the consumers; batching for producers; and how multiple producers work. ProducerBarriers The Disruptor code has interfaces and helper classes for the Consumer s, but there's no interface for your producer, the thing that writes to the ring buffer.  That's because nothing else needs to access your producer, only you need to know about it.  However, like the consuming side, a ProducerBarrier is created by the ring buffer and your producer will use this to write to it. Writing to the ring buffer involves a two-phase commit.  First, your producer has to claim the next slot on the buffer.  Then, when the producer has finished writing to the slot, it will call commit on the ProducerBarrier . So let's look at the first bi
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Dissecting the Disruptor: How do I read from the ring buffer?

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The next in the series of understanding the Disruptor pattern developed at LMAX . After the last post we all understand ring buffers and how awesome they are.  Unfortunately for you, I have not said anything about how to actually populate them or read from them when you're using the Disruptor. ConsumerBarriers and Consumers I'm going to approach this slightly backwards, because it's probably easier to understand in the long run.  Assuming that some magic has populated it: how do you read something from the ring buffer? (OK, I'm starting to regret using Paint/ Gimp .  Although it's an excellent excuse to purchase a graphics tablet if I do continue down this road.  Also UML gurus are probably cursing my name right now.) Your Consumer is the thread that wants to get something off the buffer.  It has access to a ConsumerBarrier , which is created by the RingBuffer and interacts with it on behalf of the Consumer .  While the ring buffer obviously needs a se
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